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inc/FIFO.c

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+// FIFO.c
+// Runs on any Microcontroller
+// Provide functions that initialize a FIFO, put data in, get data out,
+// and return the current size.  The file includes a transmit FIFO
+// using index implementation and a receive FIFO using pointer
+// implementation.  Other index or pointer implementation FIFOs can be
+// created using the macros supplied at the end of the file.
+// Daniel Valvano
+// November 18, 2022
+
+/* This example accompanies the book
+   "Embedded Systems: Real Time Interfacing to the Arm Cortex M3",
+   ISBN: 978-1463590154, Jonathan Valvano, copyright (c) 2011
+   Programs 3.7, 3.8., 3.9 and 3.10 in Section 3.7
+
+ Copyright 2022 by Jonathan W. Valvano, valvano@mail.utexas.edu
+    You may use, edit, run or distribute this file
+    as long as the above copyright notice remains
+ THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
+ OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
+ MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
+ VALVANO SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL,
+ OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
+ For more information about my classes, my research, and my books, see
+ http://users.ece.utexas.edu/~valvano/
+ */
+#include <ti/devices/msp/msp.h>
+#include "../inc/FIFO.h"
+
+// Two-index implementation of the transmit FIFO
+// can hold 0 to TXFIFOSIZE-1 elements
+uint32_t volatile TxPutI; // where to put next
+uint32_t volatile TxGetI; // where to get next
+char static TxFifo[TXFIFOSIZE];
+
+void TxFifo_Init(void){
+  TxPutI = TxGetI = 0; // empty
+}
+int TxFifo_Put(char data){
+uint32_t newPutI = (TxPutI+1)&(TXFIFOSIZE-1);
+  if(newPutI == TxGetI) return 0; // fail if full
+  TxFifo[TxPutI] = data;          // save in Fifo
+  TxPutI = newPutI;               // next place to put
+  return 1;
+}
+char TxFifo_Get(void){char data;
+  if(TxGetI == TxPutI) return 0;      // fail if empty
+  data = TxFifo[TxGetI];              // retrieve data
+  TxGetI = (TxGetI+1)&(TXFIFOSIZE-1); // next place to get
+  return data;
+}
+uint32_t TxFifo_Size(void){
+  return (TxPutI-TxGetI)&(TXFIFOSIZE-1);
+}
+
+// Two-index implementation of the receive FIFO
+// can hold 0 to RXFIFOSIZE-1 elements
+uint32_t volatile RxPutI; // where to put next
+uint32_t volatile RxGetI; // where to get next
+char static RxFifo[RXFIFOSIZE];
+
+void RxFifo_Init(void){
+  RxPutI = RxGetI = 0;  // empty
+}
+int RxFifo_Put(char data){
+uint32_t newPutI = (RxPutI+1)&(RXFIFOSIZE-1);
+  if(newPutI == RxGetI) return 0; // fail if full
+  RxFifo[RxPutI] = data;          // save in Fifo
+  RxPutI = newPutI;               // next place to put
+  return 1;
+}
+char RxFifo_Get(void){char data;
+  if(RxGetI == RxPutI) return 0;      // fail if empty
+  data = RxFifo[RxGetI];              // retrieve data
+  RxGetI = (RxGetI+1)&(RXFIFOSIZE-1); // next place to get
+  return data;
+}
+uint32_t RxFifo_Size(void){
+  return (RxPutI-RxGetI)&(RXFIFOSIZE-1);
+}
+